Device without losses depending from the principle, for freeing electrical or electronic one-way switches from a high power loss stress when they are switching on and off, as well as from increased blocking voltage stress following with their being switched off

摘要

With respect to the best-possible utilisation of their electrical limiting data, and taking into account their thermal stress and the losses associated therewith, electrical and electronic one-way switches may not be subjected to significant power loss stress while they are being switching over. During the switching-on process of the one-way switch, simultaneous stressing of the same by high current and voltage values is prevented by switching-on relief inductors which limit the rate of current rise. The energy stored in these switching-on relief inductors is converted into resistive heat losses in known relief networks, after the one-way switch is switched off. In contrast, in the case of the device according to the invention and shown by way of example in Fig. 9, this energy is initially temporarily stored in an overvoltage limiting capacitor (6) and then in an oscillation inductor (19) and is finally fed back into the supplying DC voltage system with the aid of diodes (20, 7 and 4). If this device is combined with a switching-off relief network, according to one of the German Offenlegungsschriften P 2649385, P 2650673 or P 2710938, a device is produced which frees the one-way switch of high power loss stress while it is being switched on as well as while it is being switched off, without any losses resulting from the principle. IMAGE